All Questions
Tagged with hat-guessing logical-deduction
48
questions
2
votes
0
answers
177
views
Guess Hat Collor [closed]
Five elders are sitting around a large bonfire. They know that Oluf will put a hat of one of four colours (red, green, blue or yellow) on each elder’s head, and after a short time for silent ...
2
votes
1
answer
377
views
Sheets of paper on foreheads in a quiz show [duplicate]
I have got a puzzle that I wanted to share.
In a quiz show, three candidates were shown five slips of paper - three white and two black. Then they were blindfolded and one of the slips of paper was ...
8
votes
2
answers
585
views
12 logicians each have a number written on their foreheads
12 logicians each have a number written on their foreheads, visible to all but themself. One day, a meta-logician comes by and remarks, "I see all the numbers are distinct natural numbers." ...
- 6,536
20
votes
6
answers
3k
views
A harder version of a Richard Hess logical hat problem
In the July/August 2021 issue of MIT Technology Review, there was a "logical hat" problem by Richard Hess in the Puzzle Corner. I noticed that it could be generalized. Here is the "next ...
- 551
0
votes
3
answers
214
views
Hat guessing without knowing the colors
Generalization of this problem:
Guessing hat colors. 4 prisoners
Suppose that there are $N$ prisoners, instead of $4$. Show, by finding explicitly the strategy, that if $N$ is even there is a strategy ...
- 317
5
votes
1
answer
301
views
23 people wearing hats with a bell ringing [closed]
24 extremely intelligent people get invited to a really important party. Since it's really important after 9pm (the start time of the party) a guardian will guard the door to enter the party.
All of ...
3
votes
2
answers
507
views
Sorting kids by hat colours [duplicate]
I have taken a group of students on a school trip. I want to organise them into two groups and so I have given each one a coloured hat. Some hats are red, while others are blue. Each child can see ...
- 31
4
votes
2
answers
778
views
3 hats with numbers, where 2 hats sum to the third
I have outlined a puzzle below, and provided two sources which provide answers. I am disputing that the answer provided in the sources is correct, and I am looking for others to validate or invalidate ...
- 171
5
votes
3
answers
321
views
Guess the hat colors - Riddle 7
My brother just created this puzzle for me for Halloween, at first I thought it looked simple, but then it turned out to be very challenging (at least for me!) I'll add it to my collection/app soon. I ...
- 449
2
votes
2
answers
236
views
Guess the hat colors - Riddle 6
And for today, a new original hat guessing puzzle!
CHALLENGE: Guess the hats of the 4 prisoners.
SPECIAL RULE: One of the prisoners is lying
DESCRIPTION: Each one can see the hats that are in front ...
- 449
3
votes
1
answer
411
views
Ernest does not know the color of his hat (3)
(again a more a difficult one)
The (same) premise:
An unknown number of people stands on a line playing a hat guessing game
they may not move during the game, they can only look straight ahead (each ...
- 9,366
2
votes
1
answer
239
views
Ernest does not know the color of his hat (2)
The previous version indeed proved simple; now a medium one (I think)
The (same) premise:
A number of people stands on a line playing a hat guessing game
they may not move during the game, they can ...
- 9,366
3
votes
2
answers
456
views
Ernest does not know the color of his hat
Previously I tried to make a very difficult hat color deduction puzzle: Unseen prisoners figuring out their hats
It seems to be too hard for the interested, since I did not get a complete solution.
...
- 9,366
6
votes
2
answers
815
views
Unseen prisoners figuring out their hats
A warden wants to play a game with his prisoners.
He tells them that they have to tell him the color of their own hats if they want to have dinner.
note: The warden may be mean, but the prison has a ...
- 9,366
4
votes
1
answer
221
views
Guess the hat colors - Riddle 5
I was impressed with all the answers and interesting reasoning in the previous puzzle (riddle 4). So for today I have another original hat guessing puzzle!
Challenge: guess who is wearing the green ...
- 449